<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>盒子</title>

    <style>
        .wai{
            border: 1px solid red;
            width: 200px;
            height: 200px;

            /*内边距*/
            /*如果要设置内边距.注意: 一定要结合定位技术 固定盒子*/
            box-sizing: border-box;

            padding: 50px;
        }
        .nei{
            border: 1px solid cadetblue;
            width: 100px;
            height: 100px;

            /*外边距*/
            /*margin-top: 50px;*/
            /*margin-left: 50px;*/
            /*margin-right: 50px;*/
            /*margin-bottom: 50px;*/

            /*顺时针*/
            /*margin: 50px 50px 50px 50px;*/

            /*margin: 50px;*/
        }
    </style>
</head>
<body>
    <div class="wai">
        <div class="nei"></div>
    </div>
</body>
</html>